Fenestration is generally considered to include any opening in a building's envelope, including windows, doors, and skylights. The technology applicable in the fenestration context can, however, also be applicable for other enclosure openings, such as gates in walls or fences.
There are many fenestration locking systems currently in existence. Only a few of these systems use a bendable sliding element to transfer locking motion around a corner. Among systems using a bendable sliding element are sash locking systems that have a flexible cable that extends all the way around the window. In these systems, a locking element can be pulled in two directions by opposing cables for locking and unlocking purposes. However, the cables are only used in a pulling mode; they cannot be used in a pushing mode. More typical are sash locking systems that feature a flexible push-pull member at the corner of the window frame. This push-pull member serves as a bendable sliding element and can be pulled or pushed to lock or unlock a window sash. In these systems, the flexible push-pull member is generally connected to a rigid vertical locking bar carrying the locking pins for the sash. Sash locking systems also use a variety of lever handle arrangements for moving these bendable sliding elements back and forth so as to engage or disengage a sash lock.
U.S. Pat. No. 4,887,392, issued to Lense in 1989 for an “Apparatus for Actuating and Locking a Window Sash”, provides an example of a design using a flexible push-pull member at a window corner. This patent uses a flexible tape that drives around the corner; but once the tape rounds the corner; it connects to a rigid locking bar that moves up and down to accomplish sash locking. The tape is also moved by an actuator that opens and closes the window, rather than by a separate lever.
Contrasting but related designs can be seen in U.S. Pat. Nos. 4,807,914 and 5,370,428. U.S. Pat. No. 4,807,914, issued to Fleming et al. in 1989 for a “Window Lock Assembly”, shows a locking system driven by a perforated tape. However, this tape does not extend around a corner. It merely serves as a rack driving a pinion formed as a locking cam. U.S. Pat. No. 5,370,428, issued to Dreifert et al. in 1994 for a “Mechanism for Releasably Locking Sashes in Door or Window Frames”, shows sash locking pins driven by a moving lock bar to which the pins are not attached. The pins are trapped for movement within guides that straddle or cover both sides of the locking bar.
Of the systems described above, those using a flexible member to form a bendable corner push-pull sliding element have proven to be simpler to construct and less expensive. However, there remains a need for improvements that will create a locking system that is similar in function, but even simpler to manufacture and operate than prior art devices. These improvements should also serve to create a single lever locking system that is more versatile and significantly less expensive to construct and install.